What is 3D Positional Sound?

[gceo]

After reading the iPhone 2.0 page.... what is "3D positional sound"?


I quote from the software update page: http://www.apple.com/iphone/softwareupdate/

"iPhone applications are unlike anything you’ve ever seen on a mobile phone. That’s because they leverage all the groundbreaking technologies in iPhone — like the accelerometer, Multi-Touch, 3D positional sound, and GPS. And they’re only a tap away at the App Store."

 

[DreamPod]

It means the App designer can tell sounds to play anywhere in 3D space around the listener. The system then takes that information and uses it to set how much of the sound comes from each ear of the headphones, and the volume of the sound, to simulate where it is in relation to the listener. The end effect isn't any different from anything any other stereo device can do, but the developer doesn't have to do any thinking about it: if they want a jet flying by the left side of the player to sound like it's doing that, the developer just puts the sound at the same position in 3D space as the jet, and it automatically gets louder as it gets closer to the player and quieter as it goes away, all within the left ear. Any other device and the developer would have to figure out themselves how to adjust the panning and volumes of the sound to simulate the changing audio position.